Today I learned that you can't use the "isindex" value for the name attribute of e.g. :
https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#attr-fe-name
Neither is an empty name allowed, but tyxml accepts both:
let _ = Tyxml.Html.(input ~a:[a_name "isindex"]) ()
let _ = Tyxml.Html.(input ~a:[a_name ""]) ()
It is personally not a problem for me, but since you advertise in the README that "TyXML is a library for building statically correct HTML5 [...] documents" I thought I would let you know :D